This invention is directed to the field of fabric and textile treatments. More specifically, this invention relates to preparations and their use in providing substantially permanent desirable characteristics to textiles.
Fabric treatments endowing particular characteristics or activity are highly desired by the apparel, home furnishings, and medical industries. However, conventional processes used to impart such characteristics often do not lead to permanent effects. Laundering or wearing of the treated fabric causes leaching or erosion of the agents responsible for imparting the desired characteristics. This deficiency has resulted in research efforts to develop durable treatments. Chemical bonding of the compounds onto the fabrics enhances their durability. Unfortunately, the required chemical modifications often cause concomitant reduction or loss of activity or other desired characteristics and must be individually developed for the different agents on a case-by-case basis. Labile or hydrolyzable linkers for direct chemical attachment or controlled release are difficult to engineer; they possess decomposition kinetics which are generally difficult to control, and they must be individually developed for the different fabrics and treatments on a case-by-case basis.
There is thus a need for a robust and precisely controllable methodology to durably attach agents to fibers, yarns, fabrics, and/or textiles (webs), without impairing the desired characteristics of the agent. Furthermore, for certain situations, there is a need to control the release of the agents over a prolonged duration (e.g., fragrances, biocides, anti-fungals, etc.).
This invention is directed to preparations useful for the permanent or substantially permanent treatment of various types of textile materials and other substrates and webs. More particularly, the preparations of the invention comprise an agent or other payload that is surrounded by or contained within a synthetic polymer shell or matrix or that has a surface coating. The shell, matrix or coating is reactive to fibers, yarns, fabrics, or webs, thus providing textile-reactive beads or matrices. The beads or matrices are micrometric or nanometric in size, and are herein referred to as xe2x80x9cnanoparticlesxe2x80x9d. The nanoparticle of the invention may comprise a polymeric shell surrounding the payload, a three-dimensional polymeric network entrapping the payload, or a reactive surface coating, all of which are encompassed under and referred to herein and in the appended claims as a xe2x80x9cpolymeric encapsulatorxe2x80x9d. By xe2x80x9ctextile-reactivexe2x80x9d is meant that the payload nanoparticle will form a strong chemical bond with the fiber, yarn, fabric, textile, finished goods (including apparel), or other web or substrate to be treated.
The polymeric encapsulator has a surface that includes functional groups that bind to the fibers, filaments or structural components or elements (referred to collectively herein and in the appended claims as xe2x80x9cfibersxe2x80x9d) of the treated textiles or other webs, thus providing permanent attachment of the payload to the fibers. Alternatively, the polymeric encapsulator includes functional groups that can bind to a linker molecule or polymer, which in turn will bind or attach the nanoparticle to the fiber. In either case, these functional groups are referred to herein as xe2x80x9ctextile-reactive functional groupsxe2x80x9d or xe2x80x9cfiber-reactive functional groupsxe2x80x9d or xe2x80x9csubstrate-reactive functional groupsxe2x80x9d.
The terms xe2x80x9cpayloadxe2x80x9d and xe2x80x9cpayload agentxe2x80x9d as used herein refer collectively to any material or agent that would be desirable for permanent attachment to or treatment of a textile or other web. Alternatively, the payload agent may be released from the cage of the payload nanoparticle in a controlled and/or prolonged fashion.
The chemical linkages on the surface of the nanoparticles do not involve the molecules of the payload. In many cases, in particular that of payload release, the payload agents are physically entrapped within the nanoparticle and require no chemical modifications of the agents themselves. The resulting nanoparticles have improved retention within and on the textile or web fiber structure without changing the inherent character of the payload agent. In other cases, the payload agents do not have inherent reactivity with fibers. In these cases, the polymeric encapsulator binds the payload to the fiber by chemical reaction with the fiber and either chemical binding or physical encapsulation of the payload agent.
The architecture of the polymeric encapsulator of the nanoparticle can be formulated and fine-tuned to exhibit controlled release of the entrapped payload, ranging from constant but prolonged release (desirable for drugs, biologic or anti-biologic agents, softeners, and fragrances, for example) to zero release (desirable for dyes, metallic reflector colloids, and sunblock agents, for example). In an encapsulated configuration, the nanoparticles will desirably insulate the payload from the skin, preventing potential allergic reactions. In addition, the nanoparticle can be designed to respond to different environmental stimuli (such as temperature, light change, pH, or moisture) to increase the rate of release, or color change at certain times or in certain selected spots or locations on the textile or finished good.
This invention is further directed to the fibers, yarns, fabrics (which may be woven, knitted, stitch-bonded or nonwoven), other textiles, or finished goods (encompassed collectively herein under the terms xe2x80x9ctextilesxe2x80x9d or xe2x80x9cwebsxe2x80x9d) treated with the textile-reactive nanoparticles. Such textiles and webs exhibit a greatly improved retention or durability of the payload agent and its activity, even after multiple washings.
Methods are provided for synthesizing a textile-reactive payload-containing nanoparticle. The preparations of the invention may be formed via one of several methods of encapsulation, such as interfacial polymerization, microemulsion polymerization, precipitation polymerization, surface coating, and diffusion. Multi-component mixture preparation followed by atomization/spraying into a drying chamber is yet another processing scheme. Reactive functional groups on the polymeric encapsulator provide a means for attaching the payload nanoparticles to textiles.
The textile-reactive preparations of the invention comprise an agent or payload surrounded by or contained within a polymeric encapsulator that is reactive to textiles or other webs, thus providing textile-reactive payload nanoparticles. The polymeric encapsulator of the nanoparticle has a surface that includes functional groups for binding or attachment to the fibers of the textiles or other webs to be treated.
The terms xe2x80x9cpayloadxe2x80x9d and xe2x80x9cpayload agentxe2x80x9d as used herein refer collectively to any material or agent that would be desirable for permanent or semi-permanent attachment to or treatment of a textile or other web. The payload may include, but is not limited to the following: bioactive or anti-microbial/fungal agents, drugs and pharmaceuticals, sunblock agents, dyes (such as iridescent dyes, fixed dyes, and dyes that respond to a particular environmental or chemical trigger such as heat, pH, carbon monoxide, sulfuric acid, or minute quantities of blood, for example), pigments, scents and fragrances, fire retardant or suppressant chemicals, metallic reflector colloids, reflective particles (such as mica), magnetic particles, thermochromic materials, insect repellents, heat-absorbing or -releasing phase change agents, fabric softeners, zeolites and activated carbon (useful for absorbing environmental hazards such as toxins and chemicals including formaldehyde). While the following discussions herein are directed to certain exemplary agents, it is important to note that other materials having any desirable activity suitable for textile treatments may also be encapsulated according to the teachings herein and are included within the scope of this invention.
The nanoparticles of the invention are formed by contacting an agent or other payload with a set of monomers, oligomers, or polymers (referred to herein as a xe2x80x9cpolymeric setxe2x80x9d). The monomers, oligomers, or polymers assemble around the payload. The polymeric set is then polymerized around the payload. In some cases the polymeric set will bind directly to the payload. The result is a polymeric encapsulator surrounding the payload agent. The polymeric set includes at least some components that provide reactive xe2x80x9chooksxe2x80x9d or functional groups on the surface of the final polymeric nanoparticle, which will bind, either directly or via linker molecules or polymers, to the textile structural members or web fibers to be treated.
Alternatively, a nanoparticle having functional groups on its surface can first be prepared by polymerizing a polymeric set, after which a payload can be exposed to the nanoparticle under suitable conditions such that the payload is absorbed into and entrapped in the polymeric network, to provide the textile-reactive payload nanoparticle of the invention.
Particular monomers, oligomers, or polymers useful in forming the nanoparticles of the present invention are those that contain amine, hydroxyl, sulfhydryl, or haloalkyl monomers or polymers combined with amine-, hydroxyl-, sulfhydryl-, or haloalkyl-reactive monomers or polymers. Specific examples include, but are not limited to, monomers or polymers of maleic anhydride and a di- or polyamine (monomer or polymer), and functionalized alkoxy- and halo-silanes. Presently preferred monomers are anhydrides and alkoxy- and halo-silanes. Other free-radical polymerizable reactive groups that can be used are acrylates, methacrylates, vinyl ethers, esters of maleic acid, butadiene and its derivatives, acrylamides, etc. Examples of hydrophilic and hydrophobic monomers are listed below. Many of these monomers are commercially available, for example from Polysciences, Inc., Warrington, Pa.
N-(tert-Butyl)acrylamide
n-Decyl acrylamide
n-Decyl methacrylate
N-Dodecylmethacrylamide
2-Ethylhexyl acrylate
1-Hexadecyl methacrylate
n-Myristyl acrylate
N-(n-Octadecyl) acrylamide
n-Octadecyltriethoxysilane
N-tert-Octylacrylate
Stearyl acrylate
Stearyl methacrylate
Vinyl laurate
Vinyl stearate
Bromopropyltrichorosilane
1H,1H,7H-Dodecafluoroheptyl methacrylate
2-Fluorostyrene
4-Fluorostyrene
1H,1H,2H,2H-Heptadecafluorodecyl acrylate
1H 1H,2H,2H-Heptadecafluorodecyl methacrylate
1H,1H-Heptafluorobutyl acrylate
1H,1H-Heptafluorobutyl methacrylate
1H,1H,4H-Hexafluorobutyl acrylate
1H,1H,4H-Hexafluorobutyl methacrylate
Hexafluoro-iso-propyl acrylate
Methacryloyl fluoride
1H,1H-Pentadecafluorooctyl acrylate
1H,1H-Pentadecafluorooctyl methacrylate
Pentafluorophenyl acrylate
Pentafluorophenyl methacrylate
2,3,4,5,6-Pentafluorostyrene
1H,1H,3H-Tetrafluoropropyl acrylate
1H,1H,3H-Tetrafluoropropyl methacrylate
2,2,2-Trifluoroethyl acrylate
2,2,2-Trifluoroethyl methacrylate
Acrylamide
Acrylic acid
N-Acryloyltris(hydroxymethyl)methylamine
Bisacrylamidoacetic acid
Glycerol mono(meth)acrylate
4-Hydroxybutyl methacrylate
2-Hydroxyethyl acrylate
2-Hydroxyethyl methacrylate (glycol methacrylate)
N-(2-Hydroxypropyl)methacrylamide
N-Methacryloyltris(hydroxymethyl)methylamine
N-Methylmethacrylamide
Poly(ethylene glycol) (n) monomethacrylate
Poly(ethylene glycol) (n) monomethyl ether monomethacrylate
2-Sulfoethyl methacrylate
1,1,1-Trimethylolpropane monoallyl ether
N-Vinyl-2-pyrrolidone (1-vinyl-2-pyrrolidinone)
3-aminopropyltriethoxysilane
Poly(ethylenimine)
The monomers, oligomers, or polymers may optionally be copolymerized with soft or rubbery (elastomeric) monomers or polymers to impregnate and thereby increase the durable press properties, to add to the softness, and/or to aid in the resistance to abrasive wear of the treated fabric. Alternatively, the textile-reactive nanoparticles may be applied to the fabric in conjunction with such soft or rubbery (elastomeric) monomers or polymers. The rubbery groups are selected from those groups that will provide the necessary degree of wrinkle resistance, softness, durability, strength, and abrasion resistance. Examples include, but are not limited to, polymers of isoprene, chloroprene, and polymers such as polydimethylsiloxane, polyisobutylene, poly-alt-styrene-co-butadiene, poly-random-styrene-co-butadiene, polyethylene glycol, polypropylene glycol, and copolymers of all of these.
The textile-reactive hooks or functional groups on the surface of the textile-reactive nanoparticles are selected from those groups that will bind chemically with a particular structural element, fiber, yarn, fabric, or finished good. For example, all cellulosic-based webs contain hydroxyl groups. Wool and other proteinaceous animal fibers, silk, and regenerated proteins contain hydroxyl, amine, carboxylate, and thiol groups (the latter as disulfides). It is desirable for the reactive monomers to contain functional groups that are reactive to the fiber. For example, the reactive monomers may contain adjacent carboxyl groups that can form five- and six-membered cyclic anhydrides. The anhydrides form with the aid of a catalyst when the reactive monomer is heated and dried. These cyclic anhydrides react with fibers that contain hydroxyls or amines (e.g. cotton or wool). Alternatively, the reactive groups may contain epoxide groups or epoxide precursors, such as halohydrins. Epoxides can react with amines and hydroxyls. Also, methylolacrylamide (methylol groups are known to react with cotton, e.g. DMDHEU) may be copolymerized into the nanoparticle matrix. Anhydride groups are presently preferred.
Specific amine-reactive groups include isothiocyanates, isocyanates, acyl azides, N-hydroxysuccinimide esters, sulfonyl chlorides, aldehydes, glyoxals, epoxides, oxiranes, carbonates, arylating agents, imidoesters, carbodiimides, anhydrides, and halohydrins. Carboxylate-reactive groups include diazoalkanes and diazoacetyl compounds, carbonyl diimidazole, and carbodiimides. Hydroxyl-reactive functional groups include epoxides, oxiranes, carbonyl diimidazole, N,Nxe2x80x2-disuccinimidyl carbonate or N-hydroxysuccinimidyl chloroformate, alkyl halides, isocyanates, and halohydrins. Hydroxyl groups may also be oxidized enzymatically or with periodate. Thiol groups react with haloacetyl and alkyl halide derivatives, maleimides, aziridines, acryloyl derivatives, arylating agents, and thiol-disulfide exchange reagents such as pyridyl disulfides, disulfide reductants, and 5-thio-2-nitrobenzoic acid.
Alternatively, the payload nanoparticle has surface functional groups that will react with linker molecules, which linkers will then attach to the fiber or textile to be treated. These linker molecules may be polymers. Each linker molecule may have more than one type of functional group, but at least one of the types of functionality will belong to the fiber-reactive groups listed vide supra. The linkers may be grafted onto the payload nanoparticles prior to treatment of the textile, or they may be an individual component of the applied formulation. In the latter case, the linkers will bind to both the nanoparticles and the fibers during the curing process. In one embodiment of the invention, the encapsulated payload nanoparticles are attached via their surface functional groups to N-methylol resin compounds. These N-methylol compounds are covalently attached to the textile or web. The N-methylol-containing compounds thus act as attachment bridges or linkers between the payload nanoparticles and the textile. In the practice of the invention, the N-methylol compound may react first with either the fabric or the payload nanoparticle. An additional advantage is that the N-methylol-containing compound, when present in an appropriate amount (the manufacturer recommends 8 wt % for DMDHEU), will provide a durable press finish to the final payload-treated textile or web. Alternatively there may be two or more linker molecules that are employed to link the payload nanoparticle to the textile.
Where a controlled release of the payload on or into the textile is desired, the payload agent is embedded or entrapped within the polymeric encapsulator of the nanoparticle in a manner such that it can be released from the nanoparticle in a prolonged or otherwise controllable fashion. The release profile is programmed via the chemistry of the polymer network of the nanoparticle. The nanoparticle can be formulated with an almost infinite degree of designed characteristics via key structural features, such as crosslinking density, hydrophilic-hydrophobic balance of the copolymer repeat units, and the stiffness/elasticity of the polymer network (determined by the glass transition temperature). In addition, erodible nanoparticles can be developed to encompass dual release mechanisms of diffusion and erosion.
Furthermore, the polymeric encapsulator may contain components that react or respond to environmental stimuli to cause increased/decreased content release. xe2x80x9cSmart polymersxe2x80x9d are polymers that can be induced to undergo a distinct thermodynamic transition by the adjustment of any of a number of environmental parameters (e.g., pH, temperature, ionic strength, co-solvent composition, pressure, electric field, etc.). For example, smart polymers based on the lower critical solution temperature (LCST) transition may drastically cut off release when exposed to hot water during laundering. When cooled back to room temperature, sustained release resumes. Smart polymers may be selected from, but are not limited to, N-isopropyl acrylamide and acrylamide; polyethylene glycol, di-acrylate and hydroxyethylmethacrylate; octyl/decyl acrylate; acrylated aromatic and urethane oligomers; vinylsilicones and silicone acrylate; polypropylene glycols, polyvinylmethyl ether; polyvinylethyl ether; polyvinyl alcohol; polyvinyl acetate; polyvinyl pyrrolidone; polyhydroxypropyl acrylate; ethylene, acrylate and methylmethacrylate; nonyl phenol; cellulose; methyl cellulose; hydroxyethyl cellulose; hydroxypropyl methyl cellulose; hydroxypropyl cellulose; ethyl hydroxyethyl cellulose; hydrophobically-modified cellulose; dextran; hydrophobically-modified dextran; agarose; low-gelling-temperature agarose; and copolymers thereof. If crosslinking is desired between the polymers, multifunctional compounds such as bis-acrylamide and ethoxylated trimethylol propane triacrylate and sulfonated styrene may be employed. In presently preferred embodiments, the smart polymers comprise polyacrylamides, substituted polyacrylamides, polyvinylmethyl ethers, and modified celluloses.
Where it is desirable for the payload to be visible (when it is a dye, a UV protector, or a metallic reflector, for example), the nanoparticle or the surface coating thereof will be constructed of optically transparent or translucent material, allowing light to come into contact with the payload and be reflected, refracted or absorbed.
The polymeric set can be chosen to give either hydrophobic or oleophilic nanoparticles, allowing a wider array of bioactive compounds or drugs to be comfortably entrapped within. Where the particles are hydrophilic, they are easily dispersible in a stable aqueous suspension or emulsion by surfactants, which can subsequently be washed away without affecting the performance of the payload agent within. The inherent thermodynamic compatibility of the agents and polymeric encapsulator material can increase the loading level per particle.
The textile-reactive payload nanoparticles of the invention are present in their final form as beads or particles having a diameter of from a few microns to a few nanometers, preferably from about 1 to about 1000 nm, more preferably from about 10 to about 500 nm. The size of the textile-reactive nanoparticles will primarily be chosen for the best penetration into the particular fiber to be treated. Additionally, the particles can be engineered to have either a narrow or a broad size distribution, depending on the intended release profile of the active agent.
The textile-reactive nanoparticles of the present invention can be formed in several ways, with the exact procedure for bead or particle formation being determined by processing features. These features include, but are not limited to, the solubility of the payload agent and/or the monomers/oligomers/polymers of the polymeric set; light stability, heat stability, and mechanical stability of the polymeric set as well as of the nanoparticle; and the like. Additional considerations, such as the desired properties of the resulting textile-reactive nanoparticles and their fiber-specific binding properties, may also dictate the exact formulation procedure required. Generally, to form the textile-reactive payload nanoparticle, the target payload agent is dissolved or dispersed in a suitable medium and a polymeric set, including appropriate textile-reactive hooks or functional groups, is added. The monomers, oligomers, or polymers of the polymeric set are then subsequently polymerized, giving the textile-reactive payload nanoparticle. Alternatively, the payload (particularly when it is a particulate) can be directly exposed to the coating polymeric set, without solvation or emulsification. The exposed particles may then be subjected to the required conditions (e.g. heat, pH, light, vacuum and so forth) to xe2x80x9csetxe2x80x9d the polymer network or surface coating.
Water-in-oil emulsification, a technique known to those of skill in the art, is one effective embodiment of the process for the synthesis of fiber-reactive payload nanoparticles. In this technique, water-soluble monomers of the polymeric set and the water-soluble payload agent are dissolved or dispersed in an aqueous medium, to which is then added an organic solvent and an emulsifier. The aqueous phase forms a fine emulsion comprising microspheres of the payload agent and the polymeric set in the continuous organic phase. An oil-soluble polymer or other compound having textile-reactive functional groups and monomer-reactive functional groups (the oil-soluble component of the polymeric set) is added to the emulsion. The oil-soluble compound crosslinks the polymeric set and forms a polymer shell (the polymeric encapsulator) around the aqueous microspheres, thus encapsulating the payload agent. The resultant nanoparticle has textile-reactive functional groups on its surface capable of attachment to the fibers of a textile or web. In this method, a presently preferred oil-soluble polymer is poly(maleic anhydride) or poly(styrene-co-maleic anhydride).
Where a particular payload agent is water-insoluble (such as indigo dye, for example), it may be converted to a water-soluble form (to leuco indigo, in the case of indigo) prior to reaction with the monomers, oligomers, or polymers and the oil-soluble compound following the above method. After the nanoparticle formation is completed, the payload is converted back to its water-insoluble form within the nanoparticle (by oxidation of leuco indigo, in the case of indigo).
Oil-in-water emulsification, a technique known to those of skill in the art, is another effective embodiment of the process for the synthesis of fiber-reactive payload nanoparticles. In this embodiment, a water-insoluble payload agent is dissolved in an organic solution with a polymer that includes an excess of textile-reactive functional groups. The organic solution containing the payload agent is added to an aqueous medium containing an emulsifier and a polymeric set that is reactive with the first, oil-soluble polymer, thus permitting some of the functional groups of the polymeric set to crosslink with the oil-soluble polymer to form a polymer shell (the polymeric encapsulator) around particles of the agent. The resulting textile-reactive payload nanoparticle encapsulates the payload agent and has uncrosslinked textile-reactive functional groups on its polymer surface capable of attachment to the fibers of a textile or web to be treated. In this method, a presently preferred oil-soluble polymer is styrene-maleic anhydride copolymer.
In a third embodiment of a method according to the invention, polymer nanoparticles having textile-reactive functional groups on their surfaces are prepared, following procedures known in the art. These nanoparticles are then placed into a solvent that causes them to swell, opening pores or passages in the wall of the nanoparticle. A payload agent placed in this mixture will diffuse into the swollen nanoparticles. The payload-agent-infused swollen nanoparticles are then treated with a second solvent that collapses their walls, thus providing textile-reactive nanoparticles with an entrapped payload agent.
The polymeric nanoparticles of the invention may also be prepared by atomization. A solution of the bead-forming polymer is formed from a polymeric set with a suitable solvent, and the payload is added to the solvated polymer. If the payload is a solid, it may either be solubilized in the solvent or, if it is insoluble in the solvent, it should be of a sufficiently small size and well dispersed in the polymeric solution. The polymer solution is then atomized into a drying gas atmosphere where solvent removal proceeds by simple evaporative drying. Such atomization techniques include high-pressure atomization, two-fluid atomization, rotary atomization, and ultrasonic atomization. The type of technique used, as well as the operating parameters, will depend on the desired particle or bead size distribution and the composition of the solution being sprayed. Such techniques are well taught in the literature, and ample description can be found in many texts, such as Spray Drying Handbook by K. Masters, herein incorporated by reference.
Droplet formation may also be accomplished by introducing the polymer solvent solution (containing the polymeric set and payload agent) into a second, immiscible liquid in which the polymer and payload agent are immiscible and the polymer solvent is only slightly soluble. With agitation, the polymer solution will form a suspension of spherical, finely dispersed polymer solution droplets distributed within the second liquid. The second liquid shall be chosen such that it is not a solvent for the polymer, and is somewhat incompatible with the polymer solvent such that the overall polymer solution is dispersible as discrete droplets with the second liquid. The second liquid must, however, provide a reasonable solubility for the polymer solvent such that the polymer solvent is extracted from the microdroplets in a manner analogous to evaporative drying. That is, as the microdroplets make contact with and disperse in the second, immiscible liquid, the polymer solvent is extracted from the droplets. Once sufficient solvent has been removed, the polymer will phase separate and form a polymer shell at the droplet surface, as in the case of evaporative drying. Further extraction of the solvent through the polymer shell wall results in nanoparticles composed of a polymer shell wall (the polymeric encapsulator) surrounding the payload agent.
In another embodiment of a method according to the invention, nano- or micrometer-sized particles are formed by milling of the bulk material. The materials are chosen so as to contain some surface functionality, most commonly hydroxyl groups. These particles are then treated with a polymer set chosen so as to amplify or modify the surface functionality, thus providing surface-coated nanoparticles that have amplified reactivity or have a greater variety of reactivity. In preferred embodiments, particularly with larger particle sizes, the surface coating (the polymeric encapsulator) will be further treated with long linker molecules, which will improve the reactivity of the particles with textiles and may assist in emulsifying the nanoparticles. Common non-limiting examples of the particle composition are metal and metal oxides such as silica, mica, glass, titanium dioxide, antimony oxides and ferrous and ferric oxides. The polymer set is preferably composed of functionalized alkoxy- and halo-silanes, which can be applied to the metal oxide surface by methods known to those skilled in the art. The polymer set may also be composed of a charged, textile-reactive polymer that electrostatically adheres to the particle and covalently binds to fibers. A preferred example is poly(ethylenimine) that has been grafted with an epoxide such as glycidol; this polymeric set adheres to metal oxides and can be attached to hydroxyl-containing fibers with the use of N-methylol compounds such as DMDHEU.
In forming the textile-reactive nanoparticles of the invention, additional crosslinkers or complementary reactive functionalities may also be added to the solution to bridge crosslinkable groups and to alter the crosslink density. Polymerization can be accomplished by reaction methods known in the art. The crosslinking of the monomers, oligomers, or polymers and the textile-reactive functional groups is commonly produced by heat or by radiation, such as UV light or gamma rays. Catalysts or photo- or thermal-initiators can be used to promote crosslinking. Such initiators and catalysts are well known in the art and are commercially available.
In preparing the textile-reactive nanoparticles of the invention, the process temperature can vary widely, depending on the reactivity of the reactants. However, the temperature should not be so high as to decompose the reactants or so low as to cause inhibition of the reaction or freezing of the solvent. Unless specified to the contrary, the processes described herein take place at atmospheric pressure over a temperature range from about 5xc2x0 C. to about 150xc2x0 C., more preferably from about 10xc2x0 C. to about 100xc2x0 C., and most preferably at xe2x80x9croomxe2x80x9d or xe2x80x9cambientxe2x80x9d temperature (xe2x80x9cRTxe2x80x9d), e.g. about 20xc2x0 C. The time required for the processes herein will depend to a large extent on the temperature being used and the relative reactivities of the starting materials. Following formation, the textile-reactive payload nanoparticles can be isolated by filtration, by gravity/settling/floating, by centrifugation, by evaporation, or by other known techniques. Any residual oil can be removed, if desired, by extraction with an appropriate solvent, by distillation at reduced pressure, or by other known techniques. Unless otherwise specified, the process times and conditions are intended to be approximate. Those skilled in the art of polymerization reaction engineering and materials handling engineering can readily devise the appropriate processes for the intended applications.
This invention is further directed to the fibers, yarns, fabrics, textiles, or finished goods (encompassed herein under the terms xe2x80x9ctextilesxe2x80x9d and xe2x80x9cwebsxe2x80x9d) treated with the textile-reactive nanoparticles. Such textiles or webs exhibit a greatly improved retention of the payload and its activity. By xe2x80x9cgreatly improvedxe2x80x9d is meant that the payload encapsulated in a textile-reactive nanoparticle will remain on the web and its activity will be retained to a greater degree than the payload alone, even after multiple washings. For example, where the payload is a dye, the treated textiles or webs exhibit a greatly improved colorfastness and resistance to fading. When the payload is a reflective material, the textile exhibits a durable reflective or pearlescent sheen or shininess, dependent upon the size of the nanoparticle. Textiles or webs treated with nanoparticles containing a sunblock agent as the payload will absorb, block, reflect or otherwise prevent or substantially prevent harmful UV radiation from passing through the textile and also will not harm the textile itself. When the payload is an anti-microbial/fungal agent, a drug, a pharmaceutical or an enzyme, the bioactive agents are depleted only by programmed release from the nanoparticles and not from unintended detachment or release of the particles themselves from the web. This is due to the durability of the chemical bonds between the fibers and the functional groups of the nanoparticles.
The novel webs of the present invention include fibers and/or filaments; woven, knitted, stitch-bonded, and non-woven fabrics derived from natural, man made, and/or synthetic fibers and blends of such fibers; cellulose-based papers; and the like. They can comprise fibers in the form of continuous or discontinuous monofilaments, multifilaments, fibrids, fibrillated tapes or films, staple fibers, and yarns containing such filaments and/or fibers, and the like, which fibers can be of any desired composition. The fibers can be of natural, man-made, or synthetic origin. Mixtures of natural fibers, man-made fibers, and synthetic fibers can also be used. Included with the fibers can be non-fibrous elements, such as particulate fillers, flock, binders, sizes and the like. The textiles and webs of the invention are intended to include fabrics and textiles, and may be a sheet-like structure [woven (including jacquard woven for home furnishings fabrics) or non-woven, knitted (including weft inserted warp knits), tufted, or stitch bonded] and may be comprised of any of a variety of fibers or structural elements. The nonwovens may be stitch bonded, ultrasonic bonded, wet laid, dry laid, solvent extruded, air or gas blown, jet interlaced, hydroentangled, and the like, and may have a broad variety of properties including stretch, air permeability, or water vapor breathability. Examples of natural fibers include cotton, wool, silk, jute, linen, and the like. Examples of manmade fibers derived primarily from natural sources include regenerated cellulose rayon, Tencel(copyright) and Lyocell, cellulose esters such as cellulose acetate, cellulose triacetate, and regenerated proteins. Examples of synthetic fibers or structural elements include: polyesters (including polyethyleneglycol terephthalate), wholly synthetic polyesters, polyesters derived from natural or biological materials such as corn, polyamides (e.g. nylon), acrylics, olefins such as polyethylene or polypropylene, aramids, azlons, modacrylics, novoloids, nytrils, aramids, spandex, vinyl polymers and copolymers, vinal, vinyon, and hybrids of such fibers and polymers.
To prepare webs having a permanently attached payload, the fiber, the yarn, the fabric, or the finished good is exposed to a solution or dispersion/emulsion of the textile-reactive payload nanoparticles, by methods known in the art such as soaking, spraying, dipping, fluid-flow, padding, and the like. If needed for the attachment reaction, a catalyst is also present in the solvent or emulsion. The textile-reactive functional groups on the nanoparticles react with the textile or web, by covalent bonding, to permanently attach to the textile. This curing can take place either before or after the treated textile is removed from the solution and dried, although it is generally preferred that the cure occur after the drying step.
Alternatively, textile-reactive payload nanoparticles are suspended in an aqueous solution that contains a linker molecule (e.g. a compound having two or more N-methylol groups, such as DMDHEU or DMUG). A catalyst may also be included (e.g. for N-methylol linkers, a Lewis acid catalyst, such as MgCl2). A surfactant may be used to help suspend the particles. The fiber, the yarn, the fabric, the nonwoven web, or the finished good to be treated is then exposed to the solution containing the textile-reactive payload nanoparticles and the linker compounds, by methods known in the art (such as by soaking, spraying, dipping, fluid-flow, padding) and dried. The linkers react with the web, by covalent bonding, and the functional groups on the payload-laden nanoparticles react with the linker compounds to permanently attach the particles to the web. The binding reactions may occur before, during or after the drying process.
The concentration of the textile-reactive payload nanoparticles in solution can be from about 0.1% to about 95%, preferably from about 0.4% to about 75%, more preferably from about 0.6% to about 50%; depending, however, on the rheological characteristics of the particular polymer nanoparticle selected (such as size or material) and on the amount of payload-deposition or -activity desired.
In preparing the treated textiles and webs of the invention, the process temperature can vary widely, depending on the affinity of the textile-reactive functional groups for the substrate. However, the temperature should not be so high as to decompose the reactants or damage the web, or so low as to cause inhibition of the reaction or freezing of the solvent. Unless specified to the contrary, the processes described herein take place at atmospheric pressure over a temperature range from about 5xc2x0 C. to about 180xc2x0 C., more preferably from about 10xc2x0 C. to about 100xc2x0 C., and most preferably at xe2x80x9croomxe2x80x9d or xe2x80x9cambientxe2x80x9d temperature (xe2x80x9cRTxe2x80x9d), e.g. about 20xc2x0 C. The temperature may vary between the application step, the drying step, and the curing step. Most commonly, application of the textile-reactive payload nanoparticles will occur at RT, whereas drying and curing will occur at higher temperatures. The time required for the processes herein will depend to a large extent on the temperature being used and the relative reactivities of the starting materials. Therefore, the time of exposure of the web to the polymer in solution can vary greatly, for example from about one second to about two days. Normally, the exposure time will be from about 1 to 30 seconds. Following exposure, the treated web is dried at ambient temperature or at a temperature above ambient, up to about 90xc2x0 C. The pH of the solution will be dependent on the web being treated. For example, the pH should be kept at neutral to basic when treating cotton, because cotton will degrade in acid. Additionally, the deposition of payload nanoparticles with charged groups (e.g., amines, carboxylates, and the like) is expected to be dependent on solution pH. Salts (e.g. sodium chloride) may optionally be added to increase the rate of adsorption of anionic and cationic payload nanoparticles onto the web fibers. Unless otherwise specified, the process times and conditions are intended to be approximate.
In order to further illustrate the present invention and advantages thereof, the following examples are given, it being understood that the same are intended only as illustrative and are not in any way limiting.